Flotation frothers, also known as flotation foaming agent, is an essential flotation agent for froth flotation. The role of flotation frothers is mainly to produce a large amount of foam in the pulp, so that the available minerals are effectively enriched at the interface between air and water to create the conditions required for flotation process.The quality of flotation frothers directly affects the efficiency of mineral froth flotation.

The Working Principle of Flotation Frothers

The importance of flotation frothers in froth flotation is reflected in two aspects. On the one hand, it affects the quantity and quality of foam. On the other hand, it also affects the contact between the mineral particles, causing the separation of the hydrophobic ore particles and the hydrophilic ore particles adhering to the foam.

Commonly used flotation frothers are heteropolar surface active materials, one end of which is a non-polar hydrocarbon group, and the other end is a more hydrophilic polar group. In the slurry, the flotation frothers molecules are adsorbed at a gas-liquid interface in a certain orientation, the non-polar groups are directed to the inside of the bubble, the polar groups are oriented toward the water, and the water molecules are attracted. Therefore, the flotation frothers molecule can reduce the flow velocity and evaporation speed of the water layer between the surface of the foam, and can prevent the crack of the foam.

At the same time, the flotation frothers can make the surface of the foam elastic. When the foam is subjected to vibration or external force, the foam will deform or even rupture. However, when there are flotation frothers molecules on the surface of the foam, the orientation of the flotation frothers molecules reduces the tension on the surface of the foam. And the surface tension of the gas-liquid interface is significantly increased. On the one hand, it is advantageous to restrain the gas molecules in the foam from rushing outward, and on the other hand, the foam generates a large contraction force, and overcomes the external force that causes the foam to rupture.

Basic Methods for Determining the Foaming Performance of Flotation Frothers

There are four basic methods for determining the foaming performance of flotation frothers:

(1) Agitating the aqueous solution of the flotation frothers by hand or mechanically for several minutes, and then measuring the volume of the foam layer.
(2) Stirring in an aqueous solution of a flotation frothers with a rotating agitator or a porous disk moving up and down, and then measuring the volume of the foam.
(3) In a glass tube with a sand core fine hole bottom plate, small bubbles of air or other gas are bubbled into the aqueous solution of the tested foaming agent, and then measuring the height of the foam.
(4) Dropping the aqueous solution of a flotation frothers from a certain height, and then measuring the generated volume of the foam.

Commonly Used Flotation Frothers

1. Flotation Frothers—Pine Oil

Pine oil is a kind of flotation frothers widely used in mineral froth flotation. It is obtained by distillation of pine roots and branches. It is a kind of yellow oily liquid with strong bubble performance and no ability to collect.

Cresol acid is a by-product of the coking industry, which is a mixture of phenol, cresol and xylenol. Its foaming ability is weaker than pine oil, the resulting foam is brittle and has good selectivity, which is suitable for the preferential flotation of polymetallic sulfide minerals. But the disadvantage of cresylic acid is that it is expensive, toxic and flammable.
Like cresol acid, heavy pyridine is also a by-product of the coking industry and consists mainly of pyridine and hydrocarbon oils. As the flotation frothers, its foaming ability is not strong and has a certain ability to collector.

3. Flotation Frothers—Methyl Isobutyl Carbinol (MIBC)

Methyl Isobutyl Carbinol (MIBC) is a kind of synthetic flotation frothers with excellent performance, which is colorless and transparent. It is very popular among mine owners all over the world. The main advantage of MIBC is that it can forms uniform and smooth foam, which can reduce the impurity inclusion of the foam product and improve the concentrate quality of the product.

Flotation process has certain requirements on the quantity, size and strength of the foam. The quality of the flotation frothers has a direct influence on the flotation effect, which in turn affects the efficiency of the enterprise. Therefore, in actual production, not only the selection of suitable types of flotation frothers, but also the amount of flotation frothers should be paid attention to, and make the size, quantity and strength of the foam can reach the optimal conditions for the flotation process.